Although buying a program is a choice, no it's not something you have to do.
Windows comes with WordPad. If your formatting needs are very slight, WordPad may be adequate for you.
But WordPad is really more of a glorified text editor than a real word processor. If you want significant formatting capability, you have several choices:
- Buy Microsoft Office, which comes with Word.
- Buy Microsoft Word by itself.
- Lease Office 365 (you can't buy it), which comes with Word.
- Download and install the free OpenOffice, which comes with a word processor that's largely (but not completely) compatible with Word.
- Download and install the free LibreOffice, which comes with a word processor that's largely (but not completely) compatible with Word.
- Buy Corel WordPerfect. which is my personal favorite.
My recommendation is that you try WordPad and see whether its capabilities are adequate for your needs. As a second step, download, install and try the free LibreOffice. You may need to go no further than that.